BIRDS — GRUIDAE — GEUS. 553 



Family GEUIDAE. 



The diagnosis of this family has already been given on a preceding page. The species are 

 all very large, and inhabit dry plains rather than marshes. The bill is moderately long ; the 

 nostrils broad and pervious, the nasal groove extending but little beyond them. The legs 

 are long, but the toes are short ; the hind toe is very short and much elevated ; the claw 

 scarcely touching the ground. 



The genera are few in number, but one, Grus, belonging to North America. 



GRUS, Linnaeus. 



Grus, Linnaeus, Syst. Nat. 1735. Type ^rdea grus, L. (Gray.) 



Ch. — Bill lengthened, straight, the upper mandible only slightly decurved at the extreme tip ; the commissure and other 

 outlines straight. Nasal groove very large and open, extending over the basal two-thirds of the bill. Nostrils broadly open, 

 pervious ; the anterior extremity half way from the tip of bill to eye. The upper half of the head naked, warty, but with 

 short hairs. 



Legs much lengthened ; toes short, hardly more than one-third the tarsus. Inner toe rather longer, its claw much larger 

 than the outer. Hind toe elevated, short. Toes connected at base by membrane. Tarsi broadly scutellate anteriorly. 

 Tertials longer than primaries, decurved ; first quill not much shorter than second. Tail of twelve feathers. 



The piecise number of species of this genus in North America and their character has been 

 a matter of much uncertainty, and the subject cannot even now be said to be well settled. 

 Audubon admits but one, considering the brown sand-hill crane to be the young of the white 

 whooping crane. This, however, is erroneous, the species being perfectly distinct. Mr. 

 Cassin has detected what he considers a third species among the Smithsonian collections, to 

 which he gives the name of G, f rater cuius. He thinks also that in the same collection are 

 specimens which may even point a fourth species very similar to, if not identical with, G, 

 longirostris, Temm. 



Synopsis of species. 



A. Adult plumage white ; primaries black. Bill much longer than middle toe. 



Bill very thick ; the gonys convex, ascending ; warty portion of head extending in 

 a point backward on top of head, and behind the cheeks below the eye ; concealed 

 by black hairs G. americanus. 



B. Adult plumage plumbeous. 



Bill slender, longer than middle toe. Gonys straight ; in line with lower edge of bill. 

 Warty space of head not extending below eyeSj and bifurcated behind by the extension 

 forward in an angle of occipital feathers. Primaries brown with white shafts. 



G. canadensis. 



Much smaller. Bill shorter than middle toe. Gonys straight, but ascending. Head in 

 young feathered to bill. Primaries black, with brown shafts G. fraterculus. 



